Start PHP-FPM with root option automatically

On systemd systems, you may have to configure this via systemd rather than system V init scripts

The below steps are tested and working on Ubuntu 16.04 LTS. And this is your culprit for redirected init scripts:

/lib/lsb/init-functions.d/40-systemd

1. Edit your php-fpm pool configuration e.g. /etc/php/7.0/fpm/pool.d/www.conf and configure root as the user/group as root

; Unix user/group of processes
; Note: The user is mandatory. If the group is not set, the default user's group
;       will be used.
user = root
group = root

2. Edit /lib/systemd/system/php7.0-fpm.service and append -R to the ExecStart variable to allow the service to run as root

ExecStart=/usr/sbin/php-fpm7.0 --nodaemonize --fpm-config /etc/php/7.0/fpm/php-fpm.conf -R

3. Reload the configuration

$ systemctl daemon-reload

4. Start the service

$ systemctl start php7.0-fpm

5. Check it out

$ ps auwx | grep php
root     32061  0.0  0.0 221680 26084 ?        Ss   16:59   0:00 php-fpm: master process (/etc/php/7.0/fpm/php-fpm.conf)
root     32063  0.0  0.0 221680  4992 ?        S    16:59   0:00 php-fpm: pool www
root     32064  0.0  0.0 221680  4992 ?        S    16:59   0:00 php-fpm: pool www

I finally found a solution. It turned out Ubuntu was using systemd to start and restart PHP-FPM and was therefor ignoring the init.d files.

If you experience issues with adjustments to init.d files being ignored and you're on Ubuntu 15.04 or later, big chance that service has a systemd service file as well.

---

So the fix for my problem: My system has a file named /lib/systemd/system/php7.0-fpm.service, which is used by systemd. With the command cat /lib/systemd/system/php7.0-fpm.service you can see the content of the service file. You replace php7.0-fpm.service with the name of your service file. PHP7.0-FPM's service file looks like this:

[Unit]
Description=The PHP 7.0 FastCGI Process Manager
Documentation=man:php-fpm7.0(8)
After=network.target

[Service]
Type=notify
PIDFile=/run/php/php7.0-fpm.pid
ExecStart=/usr/sbin/php-fpm7.0 --nodaemonize --fpm-config /etc/php/7.0/fpm/php-fpm.conf
ExecReload=/bin/kill -USR2 $MAINPID

[Install]
WantedBy=multi-user.target

In my case I needed to adjust the ExecStart rule. We don't have to edit this file, because systemd offers a way to override specific rules. The command sudo systemctl edit php7.0-fpm.service will open up an editor where you can enter those rules. Just enter the section(s) of the rule(s) you want to adjust and save the file. In my case it looks like this:

[Service]
ExecStart=
ExecStart=/usr/sbin/php-fpm7.0 --allow-to-run-as-root --nodaemonize --fpm-config /etc/php/7.0/fpm/php-fpm.conf

Make sure to reset the rule you want to edit first, otherwise both rules will be executed. Also make sure to run sudo systemctl daemon-reload after saving this file. In my case running pools as root is now allowed on Ubuntu 16.04.